DESCRIPTION: This application proposes studies to develop oral rinse formulations that maximize the cariostatic effects of fluoride, while minimizing fluoride dosage and total exposure and to gain new knowledge of the anticaries mechanisms of fluoride. The proposed rinses remove a high proportion of fluoride (F) from solution and deposit it as calcium fluoride (CaF2), by hydrolyzing sodium silicofluoride (Na2SiF6) at a controlled rate such that reactants can permeate plaque prior to precipitation. The experimental strategy will use a factorial design in which in vivo plaque is exposed to rinses containing F and calcium (Ca++) at high, intermediate and low values. The F and Ca++ concentrations have been chosen to span the anticipated beneficial range. Plaque taken from the proximal zones of the premolar to second molar teeth and saliva specimens will be used in a variety of experiments and analyses utilizing methods and microanalysis techniques developed by the applicant. Sampling is to take place at 1, 3 and 8 hour intervals after rinsing, and also after a sucrose rinse that immediately follows the 3 hr and 8 hr F-rinses.Control rinses will utilize NaF at the intermediate and high F concentrations. The results of the experiments will be used to address three specific aims with each aim being carried out through a different set of experiments and/or analyses performed on the same plaque and saliva samples. In this experimental design, the specific aims are explored in parallel throughout the application. The hypotheses to be tested by the 3 specific aims are: 1. Two part F-rinses maximize F-deposition in saliva, whole plaque and plaque fluid; 2. Rinses that maximize resting plaque F, maximize plaque fluid F after sucrose exposure with plaque fluid F being negatively correlated with pH after sucrose exposure; and 3. Plaque fluid F is negatively correlated with lactate production, with maximization of resting plaque F minimizing lactate production in plaque fluid after sucrose exposure.